Hello, On Thursday, December 23, 2010 11:07 AM Russell King - ARM Linux wrote: > On Thu, Dec 23, 2010 at 06:30:57PM +0900, Kyungmin Park wrote: > > Hi Andrew, > > > > any comments? what's the next step to merge it for 2.6.38 kernel. we > > want to use this feature at mainline kernel. > > Has anyone addressed my issue with it that this is wide-open for > abuse by allocating large chunks of memory, and then remapping > them in some way with different attributes, thereby violating the > ARM architecture specification? Actually this contiguous memory allocator is a better replacement for alloc_pages() which is used by dma_alloc_coherent(). It is a generic framework that is not tied only to ARM architecture. > In other words, do we _actually_ have a use for this which doesn't > involve doing something like allocating 32MB of memory from it, > remapping it so that it's DMA coherent, and then performing DMA > on the resulting buffer? This is an arm specific problem, also related to dma_alloc_coherent() allocator. To be 100% conformant with ARM specification we would probably need to unmap all pages used by the dma_coherent allocator from the LOW MEM area. This is doable, but completely not related to the CMA and this patch series. Best regards -- Marek Szyprowski Samsung Poland R&D Center -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>